If you've just lost weight and are trying to keep it off, don't rely on diet alone to keep those unwanted pounds at bay. It may not be enough, no matter what kind of "maintenance" diet you follow, researchers say.

A team from Denmark found that people following three very different diets regained weight, anyway.

So to avoid regaining weight, "the best plan is to stick to a diet that works for you -- in combination with exercise," said study co-author Anette Due, a researcher at the University of Copenhagen.